In Thai conversation, particles (little words at the end of clauses)
are used to convey a variety of speaker's attitudes, including
degree of politeness and familiarity with addressee. Some particles
have variant forms of usage, depending on the gender of the speaker.
Polite particles belong to this group.
These particles also function as acknowledging particles, the same way 'yes'
functions.

Thais normally address people by first name rather than family name. One can add
the polite title (khun1) before the name of the addressee or person referred to,
for example: khun John, khun Mary etc. One does not refer to oneself with
(khun1) preceding the name.